Raptor Shooting Systems Introduces 7 RAPTOR and 257 RAPTOR AR-15 Rounds

Arne Brennan, co-designer of the 6.5 Grendel and ammunition wizard continues to invent new cartridge options for the AR-15 rifle. Last year, Raptor Shooting Systems released the .45 Raptor, a round based on the .308 Winchester that advertises superior performance to other big bore AR-15 rounds like the .50 Beowulf, .450 Bushmaster, and .458 SOCOM. Now, Brennan’s company has announced two new smallbore rifle rounds for the AR-15, the 7mm Raptor (stylized 7 RAPTOR) and the .257 Raptor (257 RAPTOR). From the 7 RAPTOR website:

The 7 RAPTOR is a .284 caliber / 7mm AR-15 cartridge designed for target shooting and  medium game hunting out to 300 yards.

The cartridge and chamber design are optimized for AR-15 magazine loading at a 2.26 inch overall length using AR-15 standard 5.56 bolt and magazines.

The 7 Raptor is ideally suited to bullets between 100 grains and 130 grains in weight.  However, the 7mm Raptor can handle 7mm bullets up to 168 grains.

So with the 6.5 Grendel project behind me, the challenge became could I develop another cartridge for target shooting and medium game hunting for use out to 300 yards and keep it cost effective and simple.

To achieve this goal, the design criteria of the cartridge specified that it possess many of the same key dimensions as the 223 Remington to allow use of the standard 5.56 bolt and magazines.    As well,  being based on the 223 Remington would give the end user an abundant source of economical brass to work with.   Finally, the design criteria required that the cartridge maintain close to a “one caliber” neck length to support the bearing surface of the bullet.   With the parameters of the parent case decided, the next step in the process became the decision on caliber.

In considering caliber options,  7mm offered improved external ballistics over 30 caliber when comparing equal bullet weights.  In comparing 7mm to 6.5mm, 7mm bullets are shorter, when comparing bullets of equal weight, preserving powder capacity in a small capacity case constrained to 2.26″ OAL.  In addition, it was found that a 7mm cartridge would not interfere with the forward ribs of standard 5.56 AR15 magazines allowing loading to 2.26 inches without restriction.

In creating the final design, the cartridge is able to be formed from either 223 Remington or 222 Remington brass with a full “one caliber” neck length for proper bullet bearing surface support.   Finally, the case capacity and caliber combination  proved ideal for widely available powders such as AA5744, AA1680, AA2200, Reloader 7, H4198 and Vihtvouri N120.

While others have attempted wildcats that amount to a shortened 7 TCU, the 7 RAPTOR is not a shortened 7 TCU.    The 7 TCU is created by necking up the 223 Remington and fireforming the case to create a 40 degree shoulder and remove the body taper.   Shortened versions are created by machining the base of TCU dies and by holding short a standard 7 TCU reamer.   In contrast, the 7 RAPTOR retains the body taper of the 222 Remington and forms the shoulder angle at the same time as expanding the neck from .224 to .284 with the full length resizing die and tapered expander.  Since the 7 RAPTOR is designed for a semi-automatic rifle, clearances were introduced to enhance feeding and extraction compared to the 7 TCU which was designed for a single shot handgun or bolt action rifle.  Taken further, the throat design of the 7 RAPTOR was created for a 2.26″ overall cartridge length using the ideal bullets in the 100 to 130 weight range.   In comparion, the throat design of the 7 TCU was designed for loading bullets “long” to overall lengths as great as 2.5 inches and this would create excessive free-bore even when shortening the cartridge from the back end.

The 7 RAPTOR website lists these performance figures for the cartridge, from a 24″ barreled AR-15:

May 4, 2015 Field Test Report

Speer 110 Grain TNT: 2710 fps obtained with both AA1680 and AA5744

Speer 130 Grain BTSP: 2435 fps using AA1680

Nosler 150 Grain Accubond Long Range: 2075 fps using AA1680

All tests were performed at cartridge OAL of 2.26 inches using Winchester 223 Remington brass that had been formed and trimmed to 7 RAPTOR.

The 7 RAPTOR differs from the recently released Kramer Defense 6.8×45 UCC by using .284″ bullets instead of .277″ bullets, and having a 5mm shorter case with correspondingly reduced powder capacity and increased space for a more slender projectile ogive.  Unlike the 6.8×45 UCC, the 7 RAPTOR is intended as a dedicated 300 yard medium game hunting cartridge, for which it is broadly suitable with appropriate-length barrels.

The 257 RAPTOR is intended as a medium game and varminting round. Interestingly, a similar relationship exists between the 257 RAPTOR and the .25-45 Sharps. The Sharps round, like the 6.8×45 UCC, chases high muzzle velocity over all over characteristics, within the confines of the .223 case. In contrast, the 257 RAPTOR accepts a reduced case capacity through a shortened .223 or .222 Remington case, in exchange for allowing slender, higher-BC bullets that retain energy well. As the 257 RAPTOR website points out, the .25-45 Sharps doesn’t get much benefit from its longer case, anyway, as the seating depth of the bullet eats up much of the earned case capacity.

UPDATE: Arne Brennan wrote to us …

[The 7 Raptor is ] in development along with the 257 Raptor and not sure what, if any, product will ever be released. May just let people buy reamers from pacific tool and do it themselves.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


  • Esh325

    Another wildcat AR15 cartridge that will fade into obscurity.

    • 6.5x55Swedish

      Just like 300BO? 😉

      You just never know what people starts using in this industry.

      • Anon

        Hollywood needs waiters just as much as it does stars

      • Duray

        Actually the reason blackout took off is that it’s NOT a wildcat. AAC got it standardized by SAAMI, and the old 300 Whisper (which had long been another of these fairly obscure niche rounds) finally took off. So while I too get annoyed by the knee jerk whining after each new cartridge development, your rebuttal is kinda apples and oranges.

    • Shmoe

      In all fairness, these folks are obviously going after a niche market and it’s not entirely about having a “product”. I think it’s kinda cool that they’re developing a the data and tooling for folks to do it themselves if they want to (and relatively safely!). Wildcatters and handloadiers are strange and wondrous creatures.

  • smartacus

    i like the 338 Reaper better

    • Shmoe

      If barrels and tooling were as available as they are for 300 BLK, then I’d agree with you. If you want to take full advantage of the case width, it doesn’t get better than .338. And if you’re a serious handloader (and can get the barrel you want), then I suppose it doesn’t matter.

  • cpl366

    More variations of the 7MM TCU, and .25 TCU. I will be interested to see which ones are still being discussed 10 years from now.

    • FightFireJay

      Certainly what’s pushing them now is the desire to fit a certain performance level inside of the AR-15 receivers and it’s magazines. If not for that, certainly the 300 Whisper (and SAAMI version, AAC BLK) would still be fairly obscure and the 6.8 SPC would likely not have been produced like it is.

      Actually, I think the most viable wildcats (in general) are those based on the 6.8 SPC brass. It’s about as big as you can reasonably fit in the firearm with out new barrel extensions and magazine issues (6.5 LBC/Grendel not withstanding).

      As an example, there is a 6.8 SPC based wildcat with nearly 22-250 performance in n AR15, plus cats in .243, .257, and .264!

  • jay

    I so much hate this crooked pimping of some of this wildcats.

    I mean, if you brag for half a page, that you made another cartridge, perfectly tailored for AR15 and then you give us performance from a 24 inches barrel?
    Why not tell us what it does in a standard 16 inch gun?

    • I think the theory is that they’re for hunting.

      I would expect 25-30 ft/s lost per inch, though.

    • FightFireJay

      Once upon a time, 20″ was a standard barrel for the AR platform. Most hunting bolt actions have at least a 22″ barrel and many up to 24″ and even 26″.

      The advantage to many of these wildcats, however, is that you can get hunting performance in your favorite semi-auto, many with an 18″ or 20″ barrel.

      But how do you figure they are “crooked pimping”? Most folks producing wildcats will give you load data for their barrels. You’ll know EXACTLY what to expect. And thanks to internet forums, finding a support group of folks with the same calibers is easy.

  • Greg Johnson

    Get with the times. The 6.8×45 UCC was sooo 2008.

    Now we have the 277 WLV. It doesn’t require modified mags. Pushes a 90gr pill at 2500 fps from a 10.5″ barrel.

    24″ barrel. *Snort*

    • They are all a bunch of very similar rounds with very similar performance. The proponents of .277 Wolverine have not, to my knowledge, offered up any actual pressure testing to verify the performance of their round. They are merely doing the same song and dance of “we haven’t seen any pressure signs” – which ignores that flattened primers and other signs near the case head may not occur until wildly high pressures are reached. Velocity itself is a sign of high pressure, too, a fact that most of these cartridge peddlers fastidiously ignore so that they can publish higher and more impressive numbers to deceive those who don’t have a solid background in internal ballistics.

      I am not sure what is so special about pushing a light-for-caliber bullet with a mediocre BC (.156 G6) at modest velocity from a short barrel, either.

      • Greg Johnson

        i’ll have to check into the pressure issue. Darn learning.

      • FightFireJay

        And yet we (ultra gun geeks) have been producing and using wildcats safely for decades.

        I actually think that wilcatting will INCREASE thanks to the internet. I would never have done it if there weren’t fairly easy to find communities supporting it.

        I have a wildcat “270 AR” from a manufacturer that DOES have PSI trace info. And it DOES match the pressure signs we see from primers and ejector/extractor swipes.

        I think for many people, my self included, it’s as much a project just to do it. But especially for the AR15 platform, it’s about trying to eek out as much performance as possible out of a 2.295″ long cartridge (due to magazine restrictions).

        “But what can a wildcat due that my 6.8/300/25-45/etc can’t do?” Well, mine throws a 130 gr bullet at 2800 fps… with a 20″ barrel. Plenty for pigs, deer, and elk. I also have less drop and wind drift than a 6.5 grendel. And I haven’t needed to step up to the larger AR10 platform to get this performance.

        • Producing a wildcat for your own use and redlining it is one thing, but the same thing can’t be done for a production round that has to work across countless individual combinations of guns and rounds of ammunition. It’s downright silly to look at a production round’s performance figures, and then bring up someone’s handloads with a nearly identical wildcat and talk about how much better the latter round is!

          The .270 AR is based on the 6.5×47 Lapua case head – hardly comparable to the rounds we’re talking about here! If we’re talking about that class of round, we can throw in .30 RAR, the WSSM family, 7mm BR, etc, and then the .270 AR doesn’t seem all that special. Not saying it’s a bad round, or that it’s not the right round for you, just that it’s not really a fair comparison.

          Anyway, I didn’t ask what a wildcat could do that those other rounds couldn’t do, so I’m not sure why you brought that up.

          • FightFireJay

            “Anyway, I didn’t ask what a wildcat could do that those other rounds couldn’t do, so I’m not sure why you brought that up.”

            You rather broadly condemn wildcat cartridges and the folks that bring them about. You argue that they are either unsafe or unnecessary. I brought up the .270 AR a safe cartridge that also fills a particular niche.

            30 RAR – good luck finding brass, requires modified upper, lower, and mags
            WSSM / OSSM – requires modified upper, brass is also scarce
            7mm BR – no factory support, basically a wildcat, no AR15 barrels available (that I could find)

            270 AR – forms from .308/.243 brass, bone stock upper and lower (except for bolt that comes with barrel), and 6.8/6.5 mags work.

            Wildcats are not for everyone. No one is saying they are. Just because you don’t want to fool with one doesn’t mean they don’t serve a purpose and can’t do so safely.

          • I never condemned wildcatting, I said it wasn’t the same thing as factory ammunition, and that comparing what one wildcat can do with what a factory round can do is apples and oranges. This was in direct response to a commenter who attempted to do just that.

          • FightFireJay

            Aha, I see at least part of my issue. I, for some reason, incorrectly attributed this comment to you… “I so much hate this crooked pimping of some of this wildcats.” Thus, I had my panties in a wad. My apologies.

            Not that I agree with whatever sentiment that Greg was making on 6.8×45 UCC vs .277 WLV, but the UCC is not like most “factory” ammunition. It’s not SAAMI, there’s no mention of pressure testing by the creator. There is no reload data, no barrels to purchase separately, and no die sets.

            MDWS, on the other hand, has barrels, components, and tools. There is also a nice fairly active forum dedicated to hand loading.

            And from Kramer on the UCC… ” the reloading data, when made available, will operate and cycle the rifle in a normal fashion but “WILL NOT” produce the same velocity as factory ammunition.”

            So, still no load data produced and even if he did produce some, you couldn’t meet his non-SAAMI “factory” loads.

            Okay, you got me on this one too… Apples and Oranges. HAHA.

          • Mack

            what is barrel life the on .270 AR?

          • FightFireJay

            Don’t know. To the best of my knowledge, no one has shot one out yet.

            The first run of barrels were melonite treated 4150 CMV with 5r rifling. I would expect the barrel life to be better than .270 Winchester and probably slightly less than 6.8 SPC.

            Melonite / Isonite / Nitride / QPQ / etc…. barrels are gaining a reputation for long life. Depending on the specific test, I have seen some results claim 30% or even 100% increase over chrome plating. This type of barrel treatment is more and more common in both small boutique manufacturers and also the big guys like S&W and Sig.

          • FightFireJay

            Regarding pressure signs… my headspaced AR15 in 5.56 with factory ammo shows more pressure signs in the primers and brass than my wildcat does.

        • SaltyNuts

          A 130 gr bullet at 2800 fps from a 20″ barrel in AR15 platform, I want to know more!

  • Dan

    I was just saying to myself this morning, gosh I wish there was just a few more caliber options for the AR.

  • Kjk

    Is there $ in designing these obscure cartridges no one will ever use/see? Or is it just for fun? Seems like the standard cartridges work just fine

    • I remember someone joking that most wildcat cartridges were originally the product of cabin fever from long winters. I have rifle action X, a bunch of Y cases, and a handful of Z projectiles. Hmm, what can I make?

  • Gavin Greaves

    I see something in the greater than .30 round offering and the BO which I used on the w/e does Just like the 458 SOCOM which in itself is a very poor piece of brass that captures good pressure now we can have ordinary brass that also produces good pressure Like the 45 Raptor in this instance trying to compete with the Reaper family of 50 cartridges that are just rip off of other peoples work and not one of them are yet on the market and has 18 month old backorders on something never released to public.

    • Mayday

      I have built and shot the 45 Raptor. Out to 200 yards with less than a 1″ drop. Big bore hunters dream.

      • Gavin Greaves

        I’d love to build one or more than one in Australia for ou rifles out here, answer, WE DONT EXPORT. Well I do fro US to here but they only have one supplier of Barrels and dies and another supplier of brass, all this single point stuff is BS if they need to license it go ahead but they cut off their own fingers just SSK and cant get into any pie’s by being single point suppliers when I could have a smith here build me reamers and dies 1mm difference and call it something else if I really wanted to rip them off. Painful to get it done is what they are making it.

  • Clyde Bower

    Why not just go with 6.5 or 7mm TCU?
    If you can get 2100 fps with a 130 grains bullet out of a 14″ T/C barrel, I’d bet that the ballistics out of a 14, or 16″ M4, not to mention a 18 or 20″ barreled AR.
    Why do all of these ballistic “experts” try to invent the world?